The Electrochemical Hydrogen Storage Properties Of Carbon Nanotubes

We have studied the polarization, activation properties and the electrochemical hydrogen storage capability of different hydrogen storage electrodes (composing or decomposing carbon nanotubes (CNTs)) in nickel-hydride battery (MHx-Ni), and the electrochemical hydrogen storage capacities of CNTs-Ni electrodes were emphasized. The CNTs were synthesized by CVD method using rare earth alloy (LaNi₅) as catalyst and the CNTs samples were token by TEM and treated under different treatment condition. The electrochemical hydrogen storage of CNTs were compared and therefore to choose out which is the best CNTs to make an ideal hydrogen storage electrode. The improvement of preparation technique of CNTs electrodes, different ratio of active materials, forming conditions and the influence of different additives on the hydrogen storage behaviors of CNTs were all studied prominently. The pure LaNi₅ electrodes also have great electrochemical hydrogen storage ability through experiment, and the comparison of electrochemical hydrogen storage of LaNi₅ electrodes added CNTs with different ratios were practiced and an optimized ratio was worked out.(1) CNTs were synthesized by CVD method using AB5 (LaNi₅) hydrogen storage alloy as catalyst. TEM photograph were used to observe the granule shape and structure of both catalyst and production. The CNTs were purified by air and mixture acid oxidization method, and the purification results of CNTs oxidized by the two methods were distinctively compared. The difference in the electrochemical hydrogen storage capability of CNTs before and after purification was compared as well. The polarization and circular V-A performance of CNTs were investigated.(2) CNTs were treated in N₂ atmosphere with different temperature. The CNTs were activated by heat treatment in vacuum at the same time, and the electrochemical hydrogen storage capacity of CNTs before and after activation were compared. The influence of different treating temperature and different treating condition on the electrochemical hydrogen storage capability was compared.(3) The influence on the electrochemical hydrogen storage performance of CNTs with different diameters were researched and compared. Results showed that CNTs with different diameters represent a great discrepancy in the electrochemical hydrogen storage ability.